VIENNA - The death toll has risen to 21 in the extreme weather and flooding let loose by Storm Boris in central Europe, authorities said Tuesday after two more victims were reported in Poland and one in Austria.
READ: Storm Boris unleashes central Europe flooding, toll hits 11
High winds and unusually heavy rainfall have hit swathes of Austria, the Czech Republic, Hungary, Poland, Romania and Slovakia since last week.
Although the weather seemed to be stabilising in several places, the ground remained saturated and rivers were overflowing, with authorities asking people to remain cautious.
Two big cities in Poland -- Opole in the south and Wroclaw in the west -- were still awaiting the flood wave and there were concerns that the dykes there could break.
Polish police reported on Tuesday that two more people had died as a result of Storm Boris, raising the toll in the country to six.
The police said they believe all six Polish victims had drowned.
The latest were discovered in the southwestern district of Klodzko.
"The body of an 82-year-old man was discovered in a car," district police spokeswoman Wioletta Martuszewska told AFP.
"A couple of hours later, mountain rescue services said the body of a man had been found near a riverbed," she added.
There were unofficial reports of additional victims elsewhere, but police cautioned against publishing unverified information.
"We ask everyone not to report false information about the number of flood victims in the media," the police said on X, formerly Twitter.
- 'Disaster' -
A new victim was also reported on Tuesday in Austria.
An 81-year-old woman was Austria's fifth victim of the floods, a police spokesman told AFP.
The fire brigade found the woman's body on Tuesday in her flooded home in Lower Austria, the worst-impacted province in the Alpine nation.
In addition to the five people killed in Austria and six in Poland, Storm Boris has caused the deaths of seven people in Romania and three in the Czech Republic, according to the latest tallies.
Polish Prime Minister Donald Tusk on Monday announced one billion zloty ($260 million) in aid for those in Poland hit by the storm.
In Austria, on Tuesday, 26 communities were cut off and with the weather improving, "we are discovering the scale of the disaster", Lower Austrian governor Johanna Mikl-Leitner told reporters.
The largest Czech retention basin, the Rozmberk pond in the country's south, has been overflowing its banks.
Experts say climate change caused by greenhouse gas emissions generated by human activities is increasing the frequency and intensity of extreme weather events such as torrential rains and floods.
Andreas von Weissenberg of the International Federation of Red Cross and Red Crescent Societies (IFRC) said studies to determine whether climate change is linked to these events are expected in the coming months.
Von Weissenberg said local Red Cross teams were helping the rescue and evacuation efforts, including attending to people's "emotional and mental health".
He said the floods have been "branded as historic", but warned that "climate change has a way of moving the goalposts".
By Anna Maria Jakubek And Bernard Osser With Blaise Gauquelin In Vienna